Living material made from fungus could make buildings more sustainable

Fungi and bacteria could one day be part of a living building material that is able to grow and repair itself.

One of the great challenges facing the world as we attempt to reduce waste and greenhouse gas emissions is finding more sustainable building materials. The manufacture of concrete alone accounts for more than 5 per cent of total human-caused greenhouse gas emissions.

Some researchers hope to develop engineered living materials, produced from cells, that have desirable attributes such as being able to self-assemble, repair and photosynthesise. Many strong, mineralised structures exist in living organisms – such as bone and coral.

Chelsea Heveran at Montana State University and her colleagues tested whether a similar mineralised structure could be created around a scaffold of fungal mycelium. Mycelium is a network of microscopic, branching filaments that makes up part of most fungi.

Heveran and her team grew a mycelium scaffold using a species of fungus called Neurospora crassa, then applied the bacterium Sporosarcina pasteurii to the scaffold.

As the fungus and bacteria metabolised urea in their growth medium, they formed a hardened structure composed of calcium carbonate, the same compound found in eggshells and seashells.

She says the team drew inspiration from bone, in which biomineral is formed on a scaffold of collagen and other proteins. “Bone is incredibly strong and tough given how lightweight it is,” says Heveran.

Other living materials created in the lab have only stayed alive for a few days, but the structure developed by Heveran and her colleagues was viable for at least a month.

“We are excited about our results and look forward to engineering more complex and larger structures,” says Heveran. “When viability is sufficiently high, we could start really imparting lasting biological characteristics to the material that we care about, such as self-healing, sensing or environmental remediation.”

“Proposing mycelium as a scaffolding medium for living materials is a simple but powerful strategy,” says Aysu Kuru at the University of Sydney.